1. Field of the Invention
The present invention relates to a lock device for a parking brake lever, which is suitable for a parking brake device for a small-sized vehicle.
2. Description of the Prior Art
A parking brake device for a small-sized vehicle such as an electric wheelchair, is designed to be operated by a parking brake lever mounted on a steering handle, and includes a lock device for locking the parking brake lever at a brake operating position to retain the parking brake device in an operative state, when a driver has operated the parking brake lever with his or her finger from a brake releasing position to the brake operating position.
The conventional lock device includes a lever locking member which is mounted in the vicinity of the parking brake lever and which is swingably supported and biased by a spring. The lock device is designed to lock the parking brake lever by swinging the lever locking member against the resilient force of the spring to bring it into engagement with the parking brake lever after operation of the parking brake lever from the brake releasing position to the brake operating position.
In the above conventional lock device, however, the operation for actuating the parking brake device comprises two stages of operating the parking brake lever and operating the lever locking member, resulting in a lower operability. Therefore, it has been desired to develop a lock device having a parking lever that can be locked in the brake operating position through a single-stage operation.
The present invention has been accomplished with the above circumstance in view, and it is an object of the present invention to provide a lock device for a parking brake lever, wherein both of the operation of locking the parking brake lever and the operation of releasing the locking of the parking brake lever can be conducted in a single stage.
To achieve the above object, there is provided a lock device for a parking brake lever, comprising a parking brake lever which is swingably supported on a support member by a first support shaft and which is operated from a brake releasing position to a brake operating position by a driver when braking. A first resilient biasing means biases the parking brake lever toward the brake releasing position. A lever locking member is swingably supported on the support member by a second support shaft and is swung to a locking position of locking the parking brake lever at the brake operating position when braking, and is operated from the locking position toward an unlocking position by the driver when releasing the braking. A second resilient biasing means biases the lever locking member toward the locking position. A first engage portion is provided on the parking brake lever, and a second engage portion is provided on the lever lock member and is capable of being brought into engagement with the first engage portion of the parking brake lever, so that when the driver operates the parking brake lever from the brake releasing position to the brake operating position for conducting the braking, the lever locking member is swung from the unlocking position to the locking position by the resilient force of the second resilient biasing means, whereby the first engage portion of the parking brake lever is brought into engagement with the second engage portion of the lever locking member swung to the locking position to lock the parking brake lever at the brake operating position. Thus, when the driver operates the lever locking member against the resilient force of the second resilient biasing means from the locking position to the unlocking position for releasing the braking, the second engage portion of the lever locking member is disengaged from the first engage portion of the parking brake lever, and the parking brake lever is swung from the brake operating position to the brake releasing position by the resilient force of the first resilient biasing means.
With the above arrangement, when the driver operates the parking brake lever from the brake releasing position to the brake operating position for braking, the lever locking member is swung from the unlocking position to the locking position by the resilient force of the second resilient biasing means, whereby the first engage portion of the parking brake lever is brought into engagement with the second engage portion of the lever locking member in the locking position to lock the parking brake lever in the brake operating position. Therefore, the lever locking member can be operated only by operating the parking brake lever to complete the locking operation of the parking brake lever. When the driver operates the lever locking member from the locking position to the unlocking position against the resilient force of the second resilient biasing means to release the braking, the second engage portion of the lever locking member is disengaged from the first engage portion of the parking brake lever, thereby permitting the parking brake lever to be swung from the brake operating position to the brake releasing position by the resilient force of the first resilient biasing means. Therefore, the parking brake lever can be operated only by operating the lever locking member to complete the releasing operation of the locking of the parking brake lever. In this way, both of the operation of locking the parking brake lever and the operation of releasing of the locking of the parking brake lever can be carried out in a single stage, leading to a remarkably enhanced operability.